In order to realize realtime continuous variable frequency of ACAC converter,further studied the principle of ACAC frequency conversion,approximation of cosine wave crossing and the principle of double variable,then proposed the strategy research on realtime continuous frequency control of ACAC converter based on low current detection.This strategy used low current detection to judge current commutation segment and moment,calculated trigger point at point online based on approximation of cosine wave crossing.To verify the feasibility of this control strategy,set up the ACAC converter speed control system experimental platform based on stm32f103zet,and wrote the program based on the principle of double variable,approximation of cosine wave crossing and the strategy of low current detection.Experimental results showed that the strategy has better control performance.